Liposome measurement

Measure the fluorescence intensity of di-8ANEPPS-stained liposomes of different sizes.
Conclusion:
The fluorescence of di-8-ANEPPS-stained liposomes is proportional to liposome surface area. Instrument performance was characterized using a combination of multi-intensity multifluorophore beads (Rainbow, Spherotech) and multi-intensity single fluorophore beads (Quantum FITC, Bangs) whose intensity had been calibrated in units of MESF. Linear regression of the bead MFI vs MESF was used to create a standard curve to assign MESF values to the multifluorophore beads measured under the same instrument conditions (laser power, filters, flow rates). The instrument performance was characterized in terms of Q (detection efficiency) and B (background), essentially as described by Hoffman(21). A spreadsheet model (27) was used to simulate expected intensity histograms from particles of defined intensity and in instrument with those Q and B values. The values Separation (28) and Separation Index (29) were calculated.